Primary cultures and cell lines will be used to test the carcinogenicity of nickel and nickel compounds. Criteria of transformation will include colony morphology, cell growth in soft agar-containing media and proliferation of cells in appropriate hosts. These studies will be extended to include other metal carcinogens. Using a few potent metal carcinogens, the changes in cAMP-dependent and independent protein kinase activity and composition as well as phosphorylation of non-histone chromosomal proteins will be measured during and following transformation. Other mechanistic studies will include measurements of the rate of dissolution nickel compounds in media, subcellular distribution, binding to macromolecules and effects on fidelity of transcription. It is hoped that the mechanistic studies will lead to the availability of biochemical tests for carcinogenicity of metal compounds. Preliminary studies have revealed that potentially carcinogenic metals affect cAMP-dependent protein kinase phosphorylation of histones in vitro; similar in vitro tests with known non-carcinogenic metal compounds show no inhibition of the cAMP stimulated reaction. As metal carcinogens decrease fidelity of transcription and, in high enough concentrations, eventually inhibit it, these compounds seem also to inhibit phosphorylation of proteins and could possibly also affect the fidelity of protein phosphorylation which in the case of the non-histone chromosomal proteins may result in infidelity gene readout. This possibility would be tested by examining changes in the state of phosphorylation of different molecular weight classes of nuclear proteins. These experiments would be performed in the intact cell by pulse labelling with 32PO4 during and following nickel induced transformation. The nuclear proteins will be isolated and examined for differences in their composition and phosphorylation by polyacrylamide gel electrophoresis.